Don't use spirit gum! It suuuuccckkkss and is messy. Pros aide is way better. Just be sure to get some remover, because it is hard to get off otherwise.
But I would go with the magnetic lip stud anyway. It just looks better I think

And speaking of Isabela, I just wanted to share with you guys the reason I am so excited to make her costume for my friend:

I have pretty friends lol
And her grandmother taught her how to cast copper so I dont even have to worry about her crazy neck piece! Hooray!